Portable electronic devices powered by rechargeable batteries are typically shipped with a power supply unit (e.g., AC-DC adapter). The appropriate power supply unit can ensure that a device operates as desired, including (a) providing all the desired functions and (b) recharging in a certain amount of time.
Some conventional portable electronic devices can be charged from a variety of power sources, and so are sold without a power supply unit. However, such devices typically employ a low capacity battery that operates with a correspondingly low charging current limit. As a result, the vast majority of suitable power supply units (i.e., of an appropriate voltage) can be used as battery charging power supplies, as the current draw capacity is so small. Devices powered with such lower capacity batteries can provide certain types of and/or operating times.
In contrast, other portable electronic devices can provide functions having a higher power requirement, and so employ larger capacity batteries with correspondingly higher charging current limits. As but one example, portable data storage devices can often include such battery types. As a result, such conventional devices are typically sold with an appropriate power supply unit (i.e., one that provides a sufficient large charge current). Further such conventional devices can be incapable of operating in all modes with the shipped power supply, as such a power supply may not meet the charge current requirement.